[LinuxBIOS] FILO with the USB

Al Boldi a1426z at gawab.com
Sat Nov 17 18:51:02 CET 2007

Stefan Reinauer wrote:
> Al Boldi wrote:
> > The problem with the current tiny-kernel approach is that, it can't get
> > nearly as tiny as filo.  And when you have legacy systems like i440bx
> > with only 256kb flash, then tiny-kernel becomes a definite no go, which
> > make filo the only viable solution.
> >
> > What we really need is a stripped down tiny-kernel.  IOW, a single-proc
> > kernel-stub with its sole purpose to provide access to the large linux
> > driver pool.  Later, this could conceivably be inlined with the
> > LinuxBIOS code-base, making LinuxBIOS really a BIOS that makes use of
> > linux.
> I don't have good memories on this approach: MILO, the Alpha Linux
> bootloader, did exactly that. Been there, done that. I made such a stub
> for Kernels 2.2 and 2.4.

How big did the stub turn out to be?

> The one disadvantage of all Linux as Bootloader approaches is that you
> can not really fit any decent amount of drivers into any existing system
> flash. Yes it has been done as a proof-of-concept but as far as I know
> Linux-as-bootloader never made it into any product (that I know of)
> Ripping the scheduler out of Linux will get us space for another half to
> full driver ... But creating a flexible ROM that allows to use all SCSI
> controllers and boot a number of operating systems, will always fail.
> The SCSI drivers of Linux alone are more than 30MByte. Even with 128MBit
> parts we don't come anywhere close.

You wouldn't want to compile all drivers in.  Just the ones to boot the 
system, and then kexec the real kernel.

> Don't get me wrong. I do like the L-A-B approach. It's just not the
> solution to all problems.




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